Conventionally, in an engine with a supercharger, to protect a compressor and the like, there has been provided a passage which makes a portion of the air intake passage on an upstream side of the compressor and a portion of the air intake passage on a downstream side of the compressor communicate with each other thus bypassing the compressor. That is, when an amount of air sucked into the inside of the engine body is decreased at the time of deceleration or the like, pressurized air existing between the compressor and the engine body flows backward thus giving rise to a possibility that the compressor or the like is damaged. Accordingly, there has been adopted a technique where air compressed by the compressor is leaked to an upstream side of the compressor from a downstream side of the compressor through the bypass passage at the time of deceleration or the like.
However, when the bypass passage is disposed in the air intake passage, for instance, a pressure wave is propagated to an upstream side of the air intake passage through the bypass passage thus giving rise to a possibility that noises are generated. In view of the above, for example, Patent Literature 1 discloses a device provided with a passage which makes the bypass passage and an exhaust passage communicate with each other. In such a device, the inflow of pressurized air toward an air intake passage side is suppressed by introducing a portion of the pressurized air into the exhaust passage at the time of deceleration or the like and hence, the inflow of the pressurized air into the air intake passage side is suppressed.